Backlash equalizer

ABSTRACT

The present invention covers a backlash equalizer of simple and economical construction which includes isolation of input and output with no interaction during adjustment. This latter is easy to obtain.

United States Patent Related US. Application Data Continuation ofSer.No. 415,254. Nov. l2, i973.

US. Cl 64/6; 64/1 v; 614/27 R; 64/DlG. 2; 74/409 1111. c1. Fl6d 3/00Field of Search 64/6. 4. l V. DIG. 2. 27 R; 74/409. 526. 10.2

- Bergson Apr. 8, 1975 [54] BACKLASH EQUALIZER 2.552.682 5/1951 Lopez64/6 2119111 11 9/1956 B 1... 74/4/19 [761 Cwlrhmuk 2.920.5(12 1/196064/010. 2 P l L P W 3.529.704 9/1970 Winstone et 111. 64/27 R 19095 [22]Filed: 973 Primury hmmirwr-Sanwel Scott [2] A No; 414,493 Assistantlz'.\'uminvrRandull Hezlld Attorney. Agent. or Firm-Jackson. Jackson A;

Chovunes ABSTRACT 3 Claims, 3 Drawing Figures PATENTEDAPR 8I975 SHEET 19F 2 PATENIEDAPR ems 75,761

saw 2 0F 2 FIG. 3

BACKLASH EQUALIZER CROSS REFERENCE TO OTHER APPLICATION This presentapplication in view of its presently accorded filing date of Dec. 12,1973. constitutes a continuation of Gustav Bergson US. application Ser.No. 415,254. filed Nov. 12. I973.

DESCRIPTION My invention relates to a backlash equalizer. including botha specific device for this purpose, and a setup as part of which thisdevice can operate with good results and which also illustrates the wayin which it can cooperate with other things.

A purpose of my invention is to make such an equalizer which shall be atonce especially economical. especially compact and have a relativelywide range.

Further purposes will appear in the remainder of the specification andthe claims.

My invention is illustrated in the drawings by an embodiment chosen fromthe standpoint of convenience in illustration, satisfactory operationand clear demonstration of the principles involved.

FIG. 1 is a view partly in elevation and partly in section of thisembodiment of the specific device for the purpose of equalizingbacklash.

FIG. 2 is another view of the same entirely in elevation. but withdirection of view changed or the entire device rotated so that theopening in the cylindrical member 3, which is at the top in FIG. I, isdirectly in front in FIG. 2.

FIG. 3 is a schematic view of the entire setup with the antibacklashcoupling seen from the same side as that from which it is seen in FIG.2.

In the field of instrumentation it is sometimes re quired to have ameans of locally indicating the position in a mechanical system. whichmay include bearing or other coupling means, of a remote member whichmay be a cam cutting off a light beam. The desirability of beingindependent of the direction of rotation when joined with the need for ahigh degree of accuracy makes it necessary to equalize the backlash inthe system. An example of such a need and its solution is found in themeasuring cam position indicator of the Colormaster filter colorimeterwith the use of Bergson US. Pat. No. 2,763,161. The present invention isconcerned with the same instrument and the newly arisen need for addingto the precise positioning of the indicator, the same property withrespect to the arm of a potentiometer whereby a voltage signal is to betaken off for the purpose known as computer interfacing. Mechanicalconstraints dictate the requirement that this need be treated separatelyand the economy of the present invention both in space and costrecommend it as against any effort to pursue the above mentioned patentmeans. It is a feature of the present invention that it is very easy toadjust for the position of equal backlash. A further feature is that ofpermitting a much wider range of adjustment than as compared to that ofthe Bergson patent. A still further feature is that it lends itself toproduction as a single compact unit.

The particular equalizing device could also be called an antibacklashcoupling. shown in FIG. 3, and constituting more or less the entirety ofFIGS. 1 and 2, and will be understood better if reference is made to thedrawings, depicting a specific embodiment which is merely exemplary ofmy invention.

In FIG. I, I is a first antifriction bearing and 2 is a second bearing,both mounted coaxially in the cylindrical antifriction shell 3 at theirouter antifriction raceways. 4 is a coaxial hub end of 3. 5 and 6 areretaining rings positioning the inner raceway of first bearing 1 on thecoaxial shaft 7. 8 is a straight rod projecting radially from 7 andattached to it. 9 is a rectangular slot in the shell 3. l and II areretaining rings positioning the inner raceway of the second bearing 2onto the coaxial shaft section l2. 13 is an arm mounted on 12 by meansof the flat head screw 14. I is a screw mounted on I3 at a point beyondrod or arm 8. In FIG. I the cylindrical shell 3 is shown in crosssection with the straight radial arm 8 positioned forward against thestop arm 13 and with the holding screw 15 turned in against cylindricalshell 3. In FIG. 2, 17 is an entry slot for rod 8 during assembly. Athreaded hole in the hub 4 is provided. I8 is the upper end, edge orsurface of rectangular slot 9 which is remote from curved arm l3 withrespect to straight arm 8. I9 is an annular mounting bearing formounting the whole device in some position and having within its ring anantifriction bearing mounted on hub 4, the mounting plate on the outsidebeing mounted on and stationary with the bearing's outer race, and thebearings inner race being mounted on and turning with hub 4.

In operation a first external shaft (at left in FIGS. I and 2) isattached to cylindrical shell 3 at the hub 4 using a screw for holdingand shaft 7 is connected to a second external shaft (not shown in FIGS.1 and 2) by means of a sleeve coupling. The first external shaft will beassumed for example in the specific overall setup also included in thisinvention, to control the position of an arm of a potentiometer. Thisposition determines a voltage which is indicated on a metering device.The second external shaft is part of a rotating system which includes apositioning means. which may be a knob. and a position indicator. Thepositioning means is moved in a direction to cause shaft 7 to turncounterclockwise, as viewed from the left, until straight arm 8 isagainst edge 18, thereby producing a certain reading of the positionindicator. Screw I5 is loosened and curved arm 13 is turnedcounterclockwise until it reaches straight arm 8. The positioning meansis then turned to cause shaft 7, straight arm 8 and curved arm I3 toturn clockwise until the position indicator barely moves. Screw 15 isthen screwed down and the backlash has been equalized. The adjustment tothe proper position is obtained without disturbing the relative settingof the external devices because of the utilization of the floating shaftsection 12.

In FIG. 3, which as I indicated shows a particular setup of which thedevice of FIGS. 1 and 2, denominated in FIG. 3 as antibacklash coupling,forms a part, and the first external shaft here shown as 31. As will beseen, this first external shaft 31 is in turn connected to potentiometer32 which in turn has potentiometer leads 33, 34 and 35 respectively,running into it.

At the other end of the device or antibacklash coupling which isdescribed, is shaft 7 extending to sleeve coupling which couples tosecond external shaft 4t. This in turn has on its far end bevel gear 42which cooperates with bevel gear 43 and is driven by it, bevel gear 43being on shaft 44 at the end of which is knob 45. Thus the turning ofknob 45 will have the effect of turning the antibacklash coupling andthe potentiometer.

At the other end of shaft 44 is worm gear 46 which in turn will driveworm wheel 50 of the type normally used for worm gears. which worm wheelis mounted on a shaft at the other end of which is cam 52. Cam 52 issuitably coupled as by flexible coupling member 53 to position indicator54. Cam 52 is arranged in suitable relationship to light aperture 55. Itcan for example be used in some suitable color measuring system such asespecially found in my US, patent application Serv No, 26Z.l68. filedJune 12. l972. and which is a further development of the general type ofcolor measuring system found also for example in my US. Pat. No.3.340.764 the Glasser et al. US. Pat. No 2.774.276, and the Glasser andTroy article entitled New High Sensitivity Differential Colorimeter"published in the Journal of the Optical Society of America, Vol. 42, No,9. Sept, 1952. pages 652-660.

ln operation. therefore. the input comes to the shaft 7, which ismounted on and connected to the inner race of the bearing 1. This shaft7 mounts a radial arm 8 which extends through the slot 9, and appliestorque to the arm 8. The arm 8. as the shaft 7 is continuing on anappropriate rotational direction. will be in engagement with thelongitudinal portion of the arm l3, which is mounted on a stub shaftwhich is turning with the inner race of the bearing 2. or the edge [8 ofthe shell 3. The output ofthe device is by a hub 4 at the other end fromthe shaft 7.

When the device is subjected to an interruption in the direction ofrotation and the rotation of the input starts in an opposite direction.the arm 8 leaves contact with the arm 13 or the edge [8 and then the arm8 comes into engagement with the opposite arm 13 or edge 18. b

as the case may be.

Thus the turning of knob 45 will also have the effect of positioning cam52 and position indicator 54. The proper adjustment of backlashequalizer will thus have the effect of equalizing the backlash asbetween the knob and the potentiometer on the one hand. and the knob andthe position indicator on the other. so that the position ofthepotentiometer and the position indicator will be the same at all times,regardless of other factors. and there will be complete consistency andinterchangeability of results between them regardless of any specialfactors.

In view of my invention and disclosure. variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art. to obtain all or part ofthe benefits of myinvention without copying the mechanism shown, and I. therefore. claimall such insofar as they fall within the reasonable spirit and scope ofmy claims.

Having thus described my invention what l claim as new and desire tosecure by Letters Patent is:

l. A coupling device including a first and second coaxial bearing means,wherein the outer raceway/s of both of said bearing means are mounted ina cylindrical shell whose output end includes connection to a firstexternal shaft. and the inner raceway of said first bear ing means ismounted in a first shaft section whose input external end is suited forconnection to a second external shaft, while there is mounted on theoutput end ofsaid first shaft section a straight radial arm whichprojects through a rectangular slot in said cylindrical shell andwherein said second bearing means has mounted at its inner raceway afloating shaft on whose input end there is mounted a stop member forsaid straight radial arm. said stop member also passing through saidrectangular slot and including a holding means.

2. A coupling device such as that of claim 1, and including an entryslot.

3-. A coupling device having a cylindrical shell, a hub coaxial with theshell at one end. first and second bearing means coaxial with the shelland each including an outer raceway mounted on the shell and an innerraceway. the bearing means being arranged coaxially along the shell, thesecond bearing means having an inner stub shaft mounted on an innerbearing raceway, a first arm extending from the stub shaft in adirection radial and then longitudinal of the shell through a slot inthe shell. means for attaching a longitudinal portion of the first armremovably to the outside ofthe shell at any of a plurality of particularcircumferential positions, a second shaft connected to the inner racewayof the first bearing means, and a second arm from the second shaftextending radially through the slot in the shell for a distancesufficient to engage when in appropriate circumferential position thelongitudinal portion of the first arm. the longitudinal position of thefirst arm and the circumferential position of the second arm beingadapted to be removably in engagement, the opposite wall of the slotbeing adapted to engage the opposite side of the second arm as analternate position.

1. A coupling device including a first and second coaxial bearing means,wherein the outer raceways of both of said bearing means are mounted ina cylindrical shell whose output end includes connection to a firstexternal shaft, and the inner raceway of said first bearing means ismounted in a first shaft section whose input external end is suited forconnection to a second external shaft, while there is mounted on theoutput end of said first shaft section a straight radial arm whichprojects through a rectangular slot in said cylindrical shell andwherein said second bearing means has mounted at its inner raceway afloating shaft on whose input end there is mounted a stop member forsaid straight radial arm, said stop member also passing through saidrectangular slot and including a holding means.
 2. A coupling devicesuch as that of claim 1, and including an entry slot.
 3. A couplingdevice having a cylindrical shell, a hub coaxial with the shell at oneend, first and second bearing means coaxial with the shell and eachincluding an outer raceway mounted on the shell and an inner raceway,the bearing means being arranged coaxially along the shell, the secondbearing means having an inner stub shaft mounted on an inner bearingraceway, a first arm extending from the stub shaft in a direction radialand then longitudinal of the shell through a slot in the shell, meansfor attaching a longitudinal portion of the first arm removably to theoutside of the shell at any of a plurality of particular circumferentialpositions, a second shaft connected to the inner raceway of the firstbearing means, and a second arm from the second shaft extending radiallythrough the slot in the shell for a distance sufficient to engage whenin appropriate circumferential position the longitudinal portion of thefirst arm, the longitudinal position of the first arm and thecircumferential position of the second arm being adapted to be removablyin engagement, the opposite wall of the slot being adapted to engage theopposite side of the second arm as an alternate position.